My 2.5yo has been sleeping very late. No naps anymore, but he never seems tired and always needs stimulation, either physical or mental. I have no clue how to tire him, he's like a puppy dog. I drop him in his room and tuck him in at 8pm (started earlier but didn't work), read him a book and leave. I check on him at 10pm, and he's never sleeping then. I tuck him back in and tell him to sleep. He sleeps very late, and I don't know why. He's not scared of dark, I don't make any noise, he's fine.